Final answer:
In prokaryotes, the energy for unwinding the DNA double helix during transcription originates from ATP hydrolysis, performed by enzymes like helicase to create the transcription bubble necessary for mRNA synthesis.
Step-by-step explanation:
The energy for opening up the DNA double helix prior to transcription in prokaryotes is derived from the hydrolysis of ATP. This process is necessary to form the transcription bubble needed for the synthesis of mRNA. Enzymes such as helicase are responsible for the separation of the DNA strands, and this activity requires the energy from ATP. The helicase unwinds the DNA by breaking hydrogen bonds between the base pairs, creating a region known as the replication fork where transcription can occur.
In prokaryotic cells, ATP synthesis is linked to the establishment of a proton gradient across the inner membrane. This gradient is utilized by an enzyme complex that converts ADP into ATP, providing the necessary energy for many cellular processes, including the initiation of replication and transcription. Therefore, the unwinding of DNA during transcription and replication in prokaryotes is driven by the energy from ATP hydrolysis.